LATCH attachement: do I have to go to dealer?

[lurky]

Hello
I have a 2007 boxster, I'm the second owner.
I'm going to be taking our 4 month old to daycare in the morning and special seating is required.
It would be much easier to secure the infant seat if the car had LATCH attachments for seating.
The manual said that the LATCH attachment is installed by the dealer and after a little research it looks like they charge $500 to do it.

I am not fond of my dealer to start with and I always try to do a job myself before spending $$$. Are the LATCH attachments available anywhere ? And are special tools needed to install them?

Thanks
P.S. a second issue is the the passenger airbag should be disabled when the infant is int he car, and the sensor should handle that, but there is also an option to enable/disable the airbag with a key, which I don't have. Again, can I obtain this W.o. dealer?